The National Security Agency is conducting what it calls "basic research" to determine whether it's possible to build a quantum computer that would be useful for breaking encryption.

The news isn't surprising—it would be surprising if the NSA wasn't researching quantum computing given the measures it's taken to undermine encryption standards used to protect Internet communications. The NSA's quantum work was described in documents leaked by Edward Snowden and published today in the Washington Post. A three-page NSA document describes a project to conduct "basic research in quantum physics and architecture/engineering studies to determine if, and how, a cryptologically useful quantum computer can be built."

This is part of a $79.7 million research program called "Penetrating Hard Targets." A project goal for fiscal 2013 was to "Demonstrate dynamical decoupling and complete quantum control on two semiconductor qubits," the basic building block of a large-scale quantum computer. The NSA description of the program says the agency will "[c]ontinue research of quantum communications technology to support the development of novel Quantum Key Distribution (QKD) attacks and assess the security of new QKD system designs."

Further Reading

There's nothing specific enough in the NSA document to conclude that the agency is any more advanced in its quantum computing research than the rest of the scientific community.

“It seems improbable that the NSA could be that far ahead of the open world without anybody knowing it,” MIT Professor of Electrical Engineering and Computer Science Scott Aaronson told the Post.

Some of the NSA's experiments are carried out "in large, shielded rooms known as Faraday cages, which are designed to prevent electromagnetic energy from coming in or out," the Post wrote. "Those, according to one brief description, are required 'to keep delicate quantum computing experiments running.'" The article noted that "the NSA appears to regard itself as running neck and neck with quantum computing labs sponsored by the European Union and the Swiss government" but has no hopes of an "immediate breakthrough."

Another NSA document describing why the agency has classified its research says it's hoping to devise ways to protect US systems against quantum attack. While the NSA wants to "develop cryptanalytic QC [quantum computers] to attack high-grade public key encryption systems," it also seeks "to protect our own systems against adversarial cryptanalytic QC efforts."